Influence of the Substrate on the Electrical Properties of Thick-Film Resistors

Studies of the linear expansion coefficients and temperature coefficients of resistance of Ru-based thick-film resistors on ZrO2, BeO, Al2O3, and steatite substrates showed that the substrate effect plays an important role in Ru-based resistors, so that, to understand the thick-film conduction mechanisms, it is necessary to take the substrate-resistor system into consideration. The minimun in the resistance-temperature curve varies for different substrates, even with resistor films of the same composition and sheet resistance. An equation is proposed which correlates the resistor gage factor with the thermal expansion coefficients of the ceramic substrate